html{
	height: 100%;
}
 body{
 	margin: 0;
 	padding: 0;
 	font-family: sans-serif;
 	background: linear-gradient(rgb(43 77 164),#ae1a1a);
 }
 
 
.login-box{
 	position: absolute;
    top: 50%;
    left: 50%;
    width: 500px ;
    height: 400px;
    padding: 45px;
    transform: translate(-50%,-50%);
    background: linear-gradient(#c63636,rgb(46 61 101));
    box-sizing: border-box;
    box-shadow: 1px 0px 20px 20px  rgba(0,0,0,.6);
    border-radius: 10px;
 }


.login-box h2{
	margin: 0 0 40px;
	padding: 0;
	color: #000;
	text-align: center;
	font-size: 45px;
}

.login-box .user-box{
	position:  relative;
}

.login-box .uesr-box input{
	width: 100%;
	padding:  5px 0;
	font-size:  16px;
	color: #fff;
	margin-bottom: 20px ;
	border:  none;
	border-bottom: 1px solid #fff;
	outline: none;
    background:  transparent;
}
 
.login-box .uesr-box label{
	position:  relative;
    top: -60px;
    left: 30px;
    padding: 20px 0;
    font-size:  20px;
    color: #fff;
    pointer-events: none;
    transition: .5s;
}

.login-box .uesr-box input:focus ~ label,
.login-box .uesr-box input:valid ~ label{
	top: -20px;
	left: 0;
	color: #03e9f4;
	font-size: 12px;
}


.login-box form a{
	position: relative;
	display: inline-block;
	padding: 10px 20px;
	color: #03E9F4;
	font-size:  16px;
	text-decoration:  none;
	text-transform: uppercase;
	overflow: hidden;
	transition: .5s;
    margin-top: 40px ;
    letter-spacing: 4px;
}

.login-box a:hover{
	background: #03E9F4;
	color: #fff;
	border-radius:  5px;
	box-shadow: 0 0 5px #03E9F4,
	            0 0 25px #03E9F4,
	            0 0 50px #03E9F4,
	            0 0 100px #03E9F4;
}

.login-box a span{
	position: absolute;
	display: block;
}

.login-box a span:nth-child(1){
	top: 0;
	left: -100%;
	width: 100%;
	height: 2px;
	background:  linear-gradient(90deg, transparent, #03e9f4);
	animation: btn-anim1 4s linear infinite;
	
}

@keyframes btn-anim1 {
	0%{
		left: -100%;
	}
	50%,100%{
		left: 100%;
	}
}

.login-box a span:nth-child(2){
	right: 0;
	top: -100%;
	width: 2px;
	height: 100%;
	background:  linear-gradient(180deg, transparent, #03e9f4);
	animation: btn-anim2 4s linear infinite;
	animation-delay: 1s
}

@keyframes btn-anim2 {
	0%{
		top: -100%;
	}
	50%,100%{
		top: 100%;
	}
}

.login-box a span:nth-child(3){
	bottom: 0;
	right: -100%;
	width: 100%;
	height: 2px;
	background:  linear-gradient(270deg, transparent, #03e9f4);
	animation: btn-anim3 4s linear infinite;
	animation-delay: 2s
}

@keyframes btn-anim3 {
	0%{
		right: -100%;
	}
	50%,100%{
		right: 100%;
	}
}

.login-box a span:nth-child(4){
	left: 0;
	bottom: -100%;
	width: 2px;
	height: 100%;
	background:  linear-gradient(360deg, transparent, #03e9f4);
	animation: btn-anim4 4s linear infinite;
	animation-delay: 3s
}

@keyframes btn-anim4 {
	0%{
		bottom: -100%;
	}
	50%,100%{
		bottom: 100%;
	}
}





/*第二个*/
.login-box form dd{
	float: right;
	position: relative;
	display: inline-block;
	padding: 10px 20px;
	margin-top:40px;
	color: #bdbdbd;
	font-size:  16px;
	text-decoration:  none;
	text-transform: uppercase;
	overflow: hidden;
	transition: .5s;
    letter-spacing: 2px;
}

.login-box dd:hover{
	background: navajowhite;
	color: #fff;
	border-radius:  5px;
	box-shadow: 0 0 5px #03E9F4,
	            0 0 25px #03E9F4,
	            0 0 50px #03E9F4,
	            0 0 100px #03E9F4;
}

.login-box dd span{
	position: absolute;
	display: block;
}

.login-box dd span:nth-child(1){
	top: 0;
	right: -100%;
	width: 100%;
	height: 2px;
	background:  linear-gradient(90deg, transparent, #bdbdbd);
	animation: btn-anim5 4s linear infinite;
	
}

@keyframes btn-anim5 {
	0%{
		right: -100%;
	}
	50%,100%{
		right: 100%;
	}
}

.login-box dd span:nth-child(2){
	right: 0;
	bottom: -100%;
	width: 2px;
	height: 100%;
	background:  linear-gradient(180deg, transparent, #20f388);
	animation: btn-anim6 4s linear infinite;
	animation-delay: 3s
}

@keyframes btn-anim6 {
	0%{
		bottom: -100%;
	}
	50%,100%{
		bottom: 100%;
	}
}

.login-box dd span:nth-child(3){
	bottom: 0;
	left: -100%;
	width: 100%;
	height: 2px;
	background:  linear-gradient(270deg, transparent, #b278ff);
	animation: btn-anim7 4s linear infinite;
	animation-delay: 2s
}

@keyframes btn-anim7 {
	0%{
		left: -100%;
	}
	50%,100%{
		left: 100%;
	}
}

.login-box dd span:nth-child(4){
	left: 0;
	top: -100%;
	width: 2px;
	height: 100%;
	background:  linear-gradient(360deg, transparent, #03e9f4);
	animation: btn-anim8 4s linear infinite;
	animation-delay: 1s
}

@keyframes btn-anim8 {
	0%{
		top: -100%;
	}
	50%,100%{
		top: 100%;
	}
}